Is your free will choice, here for example, to reply or not, an illusion?
There is no "free will". There is just the will of God and the will of men. The will of God is absolutely fixed on righteousness and holiness. The will of men is bent towards doing bad things. For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out. For I do not do the good I want, but the evil I do not want is what I keep on doing.
This is the plight of all men. The ONLY thing that separates Christians from non-Christians is that we serve the law of God with my mind, but with our flesh we serve the law of sin.
And I'm sure God won't mine me plagurizing Romans 7:18-25.